Benny Amore

In Vitro and In Vivo Activity of AMG 337, a Potent and Selective MET Kinase Inhibitor, in MET-Dependent Cancer Models

The MET receptor tyrosine kinase is involved in cell growth, survival, and invasion. Clinical studies with small molecule MET inhibitors have shown the role of biomarkers in identifying patients most likely to benefit from MET-targeted therapy. AMG 337 is an oral, small molecule, ATP-competitive, highly selective inhibitor of the MET receptor. Herein, we describe AMG 337 preclinical activity and mechanism of action in MET-dependent tumor models. These studies suggest MET is the only therapeutic target for AMG 337. In an unbiased tumor cell line proliferation screen (260 cell lines), a closely related analogue of AMG 337, Compound 5, exhibited activity in 2 of 260 cell lines; both were MET-amplified. Additional studies examining the effects of AMG 337 on the proliferation of a limited panel of cell lines with varying MET copy numbers revealed that high-level focal MET amplification (>12 copies) was required to confer MET oncogene addiction and AMG 337 sensitivity. One MET-amplified cell line, H1573 (>12 copies), was AMG 337 insensitive, possibly because of a downstream G12A KRAS mutation. Mechanism-of-action studies in sensitive MET-amplified cell lines demonstrated that AMG 337 inhibited MET and adaptor protein Gab-1 phosphorylation, subsequently blocking the downstream PI3K and MAPK pathways. AMG 337 exhibited potency in pharmacodynamic assays evaluating MET signaling in tumor xenograft models; >90% inhibition of Gab-1 phosphorylation was observed at 0.75 mg/kg. These findings describe the preclinical activity and mechanism of action of AMG 337 in MET-dependent tumor models and indicate its potential as a novel therapeutic for the treatment of MET-dependent tumors. Mol Cancer Ther; 15(7); 1568–79. ©2016 AACR.

Application of In Vivo Animal Models to Characterize the Pharmacokinetic and Pharmacodynamic Properties of Drug Candidates in Discovery Settings

A goal of preclinical discovery is the identification of drug candidates suitable for clinical testing. Successful integration of in vitro and in vivo experimental data sets can afford projections of human dose regimens anticipated to be safe and therapeutically beneficial. While in vitro experiments guide new chemical syntheses and are essential to understanding drug action and disposition, in vivo characterizations provide unique insight into complex biological systems that control concentrations at the site of action and pharmacologic response. Pharmacokinetic and pharmacodynamic (PK/PD) concepts underlying drug disposition and response provide a quantitative framework with which to identify potential clinical candidates. To improve throughput in earlier stages of drug discovery, in vivo pharmacokinetic study designs such as cassette dosing and sparse sampling schemes have been utilized. In later stages of discovery, pharmacokinetic studies using chemical inhibitors or surgical and genetic animal models are used to characterize the underlying determinants of drug disposition. In a complimentary fashion, modeling of in vivo pharmacodynamic effects may quantitatively link biomarkers to pharmacological response, validate in vitro to in vivo correlations and underwrite predictions of efficacious exposure targets. When applied to in vivo discovery data, PK/PD models have aided in understanding mechanisms of pharmacological response such as receptor theory in the central nervous system and cell turnover concepts in infectious disease and oncology. This review considers the role of in vivo testing toward understanding the pharmacokinetic and pharmacodynamic attributes of lead candidates in drug discovery.

First-in-Human Study of AMG 820, a Monoclonal Anti-Colony-Stimulating Factor 1 Receptor Antibody, in Patients with Advanced Solid Tumors

Purpose: Binding of colony-stimulating factor 1 (CSF1) ligand to the CSF1 receptor (CSF1R) regulates survival of tumor-associated macrophages, which generally promote an immunosuppressive tumor microenvironment. AMG 820 is an investigational, fully human CSF1R antibody that inhibits binding of the ligands CSF1 and IL34 and subsequent ligand-mediated receptor activation. This first-in-human phase I study evaluated the safety, pharmacokinetics, pharmacodynamics, and antitumor activity of AMG 820. Experimental Design: Adult patients with relapsed or refractory advanced solid tumors received intravenous AMG 820 0.5 mg/kg once weekly or 1.5 to 20 mg/kg every 2 weeks until disease progression, adverse event (AE), or consent withdrawal. Results: Twenty-five patients received ≥1 dose of AMG 820. AMG 820 was tolerated up to 20 mg/kg; the MTD was not reached. One dose-limiting toxicity was observed (20 mg/kg; nonreversible grade 3 deafness). Most patients (76%) had treatment-related AEs; the most common were periorbital edema (44%), increased aspartate aminotransferase (AST; 28%), fatigue (24%), nausea (16%), increased blood alkaline phosphatase (12%), and blurred vision (12%). No patients had serious or fatal treatment-related AEs; 28% had grade ≥3 treatment-related AEs. Grade 3 AST elevations resolved when treatment was withheld. AMG 820 showed linear pharmacokinetics, with minimal accumulation (<2-fold) after repeated dosing. Pharmacodynamic increases in serum CSF1 concentrations and reduced numbers of skin macrophages were observed. Best response was stable disease in 8 patients (32%). Conclusions: AMG 820 was tolerated with manageable toxicities up to 20 mg/kg every 2 weeks. Pharmacodynamic response was demonstrated, and limited antitumor activity was observed. Clin Cancer Res; 23(19); 5703–10. ©2017 AACR.

A Phase 1 study evaluating AMG 337 in Asian patients with advanced solid tumors

AMG 337, a selective small-molecule MET inhibitor, was evaluated in Asian patients with advanced solid tumors. Eligible patients orally self-administered AMG 337; the initial dose of 150 mg once daily (QD) was escalated to 300 mg QD (modified 3+3+3 design). Treatment continued until disease progression, intolerability, or death. The primary endpoint was adverse events (AEs) and clinical abnormalities defined as dose-limiting toxicities (DLTs). Secondary endpoints included other AEs, pharmacokinetics and tumor response. Eleven patients were enrolled. No DLTs occurred. The most common treatment-emergent AEs were headache (73%) and nausea (45%). Cmax and AUC0-24 exposures increased proportionally with dose; t1/2 was comparable between groups; plasma accumulation was minimal over 28 days. One patient (150 mg) had partial response; one patient (300 mg) had stable disease. Safety, tolerability, pharmacokinetics and efficacy of AMG 337 in Asian patients were consistent with those observed in Western patient populations. The study was terminated early.

Abstract CT137: First-in-human study of AMG 820, a monoclonal anti-CSF-1R (c-fms) antibody, in patients (pts) with advanced solid tumors

Background: Tumor-associated macrophages (TAMs) may contribute to tumor growth and invasion and promote an immunosuppressive tumor microenvironment, making them an attractive target for cancer immunotherapy. TAMs can be activated by the binding of colony stimulating factor-1 (CSF-1) to its receptor CSF-1R (c-fms). AMG 820 is an investigational, fully human antagonistic antibody to CSF-1R that inhibits ligand-induced receptor activation. In this open-label, sequential dose-escalation study, we evaluated the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and efficacy of AMG 820. Methods: Key eligibility criteria: age ? 18 years, advanced solid tumors relapsed or refractory to standard treatment, measurable disease per RECIST 1.1, ECOG performance status ? 2, and no primary central nervous system tumors/metastases. AMG 820 was administered by IV infusion once weekly at a starting dose of 0.5 mg/kg (cohort 1). Dosing frequency was later amended to once every 2 weeks (Q2W) with planned escalation to 1.5, 3, 6, 10, 20, and 30 mg/kg (cohorts 2–7), following a 3 + 3 design until a maximum tolerated dose (MTD, highest dose at which Results: A total of 25 pts received ? 1 dose of AMG 820: 3 pts at 0.5, 1.5, and 6 mg/kg; 4 pts at 3 and 10 mg/kg; 8 pts at 20 mg/kg. Median (range) age: 63 (48–80) years. Women: 56%. ECOG 0/1/2: 20%/76%/4%. MTD was not reached. One DLT was observed (20 mg/kg): nonreversible grade 3 hearing impairment in a female pt with anal cancer with confounding factors (prior treatment [tx] with cisplatin). Most pts (76%) had tx-related adverse events (TRAEs). Most common TRAEs (in > 10% of pts overall) were periorbital edema (11, 44%), increased aspartate aminotransferase (7, 28%), fatigue (6, 24%), nausea (4, 16%), increased blood alkaline phosphatase (3, 12%), and blurred vision (3, 12%). Grade ? 3 TRAEs were observed in 28% of pts. There were no serious or fatal TRAEs. After the first dose of AMG 820 at 20 mg/kg, mean estimates of Cmax and AUClast (AUC from time 0 to time of last sample) were 619 μg/mL and 89,200 μg•hr/mL, respectively. Both AMG 820 AUClast and Cmax increased linearly with dose, with minimal accumulation ( Conclusions: AMG 820 was tolerated with manageable toxicities up to 20 mg/kg Q2W and showed linear PK, with PD response in CSF-1 serum levels and tx-related changes in skin macrophages. These results and an increasing understanding of the role of TAMs in tumor immunosuppression provide the rationale for combining AMG 820 with other immunotherapies. Citation Format: Kyriakos Papadopoulos, Larry Gluck, Lainie P. Martin, Anthony J. Olszanski, Gateree Ngarmchamnanrith, Erik Rasmussen, Benny Amore, Dirk Nagorsen, John S. Hill, Joe Stephenson. First-in-human study of AMG 820, a monoclonal anti-CSF-1R (c-fms) antibody, in patients (pts) with advanced solid tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT137.

First-in-human study of AMG 208, an oral MET inhibitor, in adult patients (pts) with advanced solid tumors.

41 Background: AMG 208 is a small molecule MET inhibitor that suppresses proliferation and induces apoptosis in human tumor xenografts. This first-in-human study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of AMG 208. We report data from the dose escalation part of the study. METHODS Key eligibility criteria: ≥ 18 yr, advanced solid tumors, ECOG ≤ 2, and evaluable/measurable disease. Using a modified Fibonacci design, 3-9 pts were enrolled into 1 of 7 sequential dose cohorts (25, 50, 100, 150, 200, 300, and 400 mg) of AMG 208. Pts received AMG 208 orally on days 1 and 4-28 once daily. If no dose limiting toxicity (DLT) was seen on days 1-28, pts received AMG 208 once daily starting at day 36 provided pts showed no evident disease progression. In cohorts 1-3, a standard 3+3 design was followed. In cohorts 4-7, a modified 3+3+3 design was followed. RESULTS As of July 16 2012, 54 pts (25 mg [n=6], 50 mg [n=4], 100 mg [n=4], 150 mg [n=3], 200 mg [n=16], 300 mg [n=10], and 400 mg [n =11]) had received ≥ 1 dose of AMG 208. 67% were men; 19% had prostate cancer (PC). Median (range) age: 61 (39-80) yr. ECOG 0/1: 52%/48%. 6 DLTs were seen: a grade (G) 3 increased AST (200 mg), a G3 thrombocytopenia (200 mg), a G4 acute myocardial infarction (300 mg), a G3 prolonged QT (300 mg), and two G3 hypertensions (400 mg). The maximum tolerated dose was not reached. 83% of pts had tx-related adverse events (AE). Tx-related AE occurring in > 10 pts: fatigue (n=24), nausea (n=18), hypertension (n=12), and diarrhea (n=11). 24% of pts had grade ≥ 3 tx-related AE. AMG 208 was orally bioavailable with a 30-35 hr mean half-life in plasma. Exposure increased linearly with dose; accumulation at day 28 was 2.7-fold across cohorts. Of the 42 pts with available tumor response data for site reads, 1 had complete response on bone scan (PC 300 mg) while 2 had partial responses (PR; PC 400 mg and kidney cancer 200 mg; both had -33% tumor shrinkage), and 29 had stable disease (SD); 1 other PC pt had PR after data cutoff. Of the 35 pts with available tumor response data for central reads, 26 had SD. FLT and biomarker data will be presented. CONCLUSIONS AMG 208 up to 400 mg daily had manageable toxicities and showed evidence of antitumor activity, especially in prostate cancer. CLINICAL TRIAL INFORMATION NCT00813384.

Predicting the Drug Interaction Potential of AMG 853, a Dual Antagonist of the D-Prostanoid and Chemoattractant Receptor-Homologous Molecule Expressed on T Helper 2 Cells Receptors

2-(4-(4-(tert-Butylcarbamoyl)-2-(2-chloro-4-cyclopropylphenylsulfonamido)phenoxy)-5-chloro-2-fluorophenyl)acetic acid (AMG 853) is an orally bioavailable and potent dual antagonist of the D-prostanoid and chemoattractant receptor-homologous molecule expressed on T helper 2 cells receptors. The drug interaction potential of AMG 853, both as a victim and a perpetrator, was investigated using in vitro, in silico, and in vivo methodologies. Experiments in human liver microsomes (HLM) and recombinant enzymes identified CYP2C8, CYP2J2, and CYP3A as well as multiple UDP-glucuronosyltransferase isoforms as being responsible for the metabolic clearance of AMG 853. With use of HLM and selective probe substrates, both AMG 853 and its acyl glucuronide metabolite (M1) were shown to be inhibitors of CYP2C8. AMG 853 and M1 did not inhibit any of the other cytochrome P450 isoforms tested, and AMG 853 exhibited minimal enzyme induction properties in human hepatocytes cultures. In light of the in vitro findings, modeling and simulation approaches were used to examine the potential for ketoconazole (a CYP3A inhibitor) to inhibit the metabolism of AMG 853 as well as for AMG 853 to inhibit the metabolism of paclitaxel, rosiglitazone, and montelukast, commonly used substrates of CYP2C8. A weak and clinically insignificant drug interaction (area under the drug concentration-time curve (AUC)i/AUC <2) was predicted between ketoconazole and AMG 853. No drug interactions were predicted for AMG 853 and paclitaxel, rosiglitazone, or montelukast. Finally, administration of AMG 853 to healthy human subjects in clinical trials in the presence or absence of ketoconazole confirmed that AMG 853 is unlikely to be involved in clinically significant drug interactions.

Intestinal and hepatic first-pass extraction of the 11β-HSD1 inhibitor AMG 221 in rats with chronic vascular catheters

Abstract 1. A catheterized rat model was used to define the intestinal and hepatic components of oral bioavailability for an 11β-HSD1 inhibitor, AMG 221. These data were integrated with standard in vivo metabolism studies to elucidate the components contributing to the oral disposition of a novel drug candidate. 2. Intestinal and hepatic extraction ratios of AMG 221 obtained using a five-catheter rat model were 0.56 and 0.32, respectively. Therefore, both intestinal and hepatic extraction contributed to the first-pass component of oral bioavailability. There was no evidence for significant gut extraction of systemically administered drug. 3. Mass balance data and in vivo metabolite characterization obtained after administration of [14C] AMG 221 to rat showed that AMG 221 was completely absorbed from the gut lumen following an oral dose, primarily excreted in urine and was almost completely metabolized prior to excretion. 4. Hepatic bioavailability (FH), measured in two animals at various time points after oral dose administration was somewhat variable but generally characterized by an initial reduction during the absorption phase followed by an increase during the elimination phase, consistent with hepatic distribution of AMG 221. 5. The five-catheter rat model afforded estimates of hepatic and intestinal contribution to oral bioavailability that were used with other data to define the preclinical ADME characteristics of a drug candidate.

Abstract 3359: Translating preclinical PK/PD tumor volume modeling data to predict AMG172 PK and dose-escalation scheme in FIH.

Background: AMG 172 is an antibody drug conjugate (ADC) comprised of a human IgG1 monoclonal antibody (mAb), a non-cleavable linker (4-[N-maleimidomethyl] cyclohexane-1-carboxylate) conjugated to lysine residues in the antibody and DM1, a semi-synthetic derivative of maytansine. AMG 172 binding and internalization into target-expressing tumor cells, induces metaphase arrest and subsequent cellular apoptosis, leading to tumor cell death. AMG 172 is being developed as a treatment for clear cell renal cell carcinoma (ccRCC), and other indications, as a single agent or in combination with chemotherapy. The primary goals of this study were, 1) to predict human AMG 172 PK disposition from non-clinical data, 2) to determine AMG 172 exposure anti-tumor activity relationships in mouse xenograft models, and develop an AMG 172 anti-tumor PK/PD model, and 3) to integrate non-clinical toxicology, pharmacology and pharmacokinetic data to support selection of doses for the first in human (FIH) clinical study Materials and Methods: A PK model in cynomolgus monkey was developed from single and multiple-dose pharmacokinetics and toxicokinetics, and used to predict the human PK of AMG 172. In vivo anti-tumor activity was demonstrated by AMG 172 in human ccRCC subcutaneous tumor xenografts in mice. Tumor growth inhibition in mouse xenografts was modeled using a tumor inhibition PK/PD model. Primary model assumptions for extrapolation of non-clinical PK/PD to human were: a) AMG 172 PK can be scaled directly from cynomolgus monkey, and b) anti-tumor efficacy in mouse xenografts is drug dependent and species independent. Results: A two compartment open linear model best described AMG 172 pharmacokinetics in cynomolgus monkey. AMG 172 CL was estimated to be 9.45 mL/hr in a typical human (70 kg) based on species-invariant time scaling methods. At the STD10 in rats and the HNSTD in cynomolgus monkey, anticipated AUC margins are approximately 17.9/11.9 and 15.7/10.5 times for Q3wk/Q2wk dosing regimens, respectively, at the projected clinical starting dose of 0.15 mg/kg. Using the mouse xenograft PK and PD data, clinical dose projections were generated that attained model-based, putative target trough concentrations. Collectively, these results support potential AMG 172 dosing every 2–3 weeks, thereby providing flexibility in the clinic. Conclusions: This work demonstrates efficient integration of non-clinical toxicology, preclinical pharmacology and pharmacokinetic data in order to support rational selection of AMG 172 doses for FIH clinical studies. Citation Format: Nelson L. Jumbe, William Fanslow, Sonal Patel, Benny Amore, Marc Retter, Vincent Chow. Translating preclinical PK/PD tumor volume modeling data to predict AMG172 PK and dose-escalation scheme in FIH. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3359. doi:10.1158/1538-7445.AM2013-3359 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.